A biochemical examination of blood is generally conducted on plasma or serum as a subject. Plasma is prepared by collecting about 10 mL of venous blood by a syringe and centrifuging the venous blood. In an immune examination of an item relating to infectious diseases, serum is used as a measuring sample, but at least about 30 minutes of treatment time, which is the sum of a time for solidifying blood and a time for the subsequent centrifugation, is required for obtaining serum from whole blood.
Therefore, medical staffs require great care and time, and this is sometimes harmful to the life of a patient especially in an emergency case such as a cardiac disease. Furthermore, in an emergency operation in which an immediate judgment to determine whether or not a patient has an infectious disease such as hepatitis or HIV is required, the development of a more rapid measuring method in which an examination time after collection of blood is shorten has been desired.
Examples of immune assays include a radioimmunoassay (RIA), an enzyme immunoassay (EIA), a particle agglutination process, a counting immunoassay and the like, and in RIA and EIA, it is necessary to conduct an antigen-antibody reaction and then conduct B/F separation, and thus great care and time are required until a measuring result is obtained.
As a means that responds to this demand, a measuring method that enables the measurement of whole blood by forcedly conducting hemolysis in a latex particle turbidimetry is exemplified. For example, Patent Literature 1 suggests a whole blood immunoassay that aims at removing the effect of hemocytes without affecting an antigen-antibody reaction in a whole blood immunoassay. This immunoassay is a method including mixing a whole blood sample and immunized insoluble carrier particles to thereby allow an immuneagglutination reaction, diluting the obtained flocculated reaction mixture with an aqueous solution containing an erythrocyte-lysing agent to lyse erythrocytes to thereby prepare a measuring sample, and measuring the agglomeration degree of the measuring sample. Furthermore, Patent Literature 2 suggests an immunoassay aiming at providing data with fine accuracy, by which a measurement can be conducted conveniently within a short time without pre-treating blood by a centrifuge or the like, which uses a sample obtained by lysing hemocytes consciously and forcedly by a method that does not affect an immune reaction and combining the sample with various quantification agents. This immunoassay is a method including subjecting an antigen or antibody in a subject sample and insoluble particles on which an antibody or antigen that specifically reacts with the antigen or antibody in the subject sample is fixed, and an antigen or an antibody in a subject sample are subjected to an agglutination reaction, and measuring the change in absorbance or change in scattered light by the irradiation of the obtained flocculate mixed liquid with light, wherein whole blood is used as the subject sample, and the whole blood is forcedly lysed.